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CryoLife O'Brien aortic stentless prosthesis reoperations: clinical results and morphologic findings
Fabio Ius1, Cristina Basso, Mila Della Barbera
1Cardio-Thoracic Department, University Hospital, Udine, Italy. ius.r@libero.it
Insights
Reoperations for CryoLife O'Brien (CLOB) stentless porcine aortic prostheses are feasible. Structural valve deterioration (SVD) is primarily caused by cusp tears from lipid and calcium deposits, leading to urgent reoperations.
Area of Science:
- Cardiovascular Surgery
- Biomaterials Science
- Pathology
Background:
- The CryoLife O'Brien (CLOB) stentless porcine aortic prosthesis has demonstrated limited long-term durability.
- Mechanisms underlying structural valve deterioration (SVD) in CLOB prostheses remain incompletely understood.
Purpose of the Study:
- To review clinical experience with CLOB reoperations.
- To investigate the pathobiology of SVD in CLOB prostheses.
Main Methods:
- Retrospective review of 35 patients undergoing CLOB reoperation between March 1996 and December 2010.
- Pathological examination of nine explanted valves for SVD analysis.
- 100% complete patient follow-up.
Main Results:
- SVD was the cause of prosthesis dysfunction in 27 patients (54% urgently operated).
- Explanted valves showed calcifications, lipid insudation, cholesterol clefts, and chronic inflammation.
- Cusp commissural tearing was identified as a primary mechanism of SVD.
Conclusions:
- CLOB reoperation is a feasible procedure with satisfactory mid-term survival.
- Lipid and calcium deposits leading to cusp tears, particularly at commissures, are key mechanisms of SVD.
- These findings explain acute prosthetic incompetence and the need for urgent reoperation.
Objectives:
The CryoLife O'Brien (CLOB) stentless porcine aortic prosthesis has shown limited long-term durability, but its deterioration mechanisms have not yet been identified. The aim of this study was to review our experience with CLOB reoperations and to investigate the pathobiology of structural valve deterioration (SVD).
Methods:
Between March 1996 and December 2010, 35 patients underwent reoperation 82 ± 43 months after a CLOB implant. Patient records were retrospectively reviewed and follow-up was 100% complete. Nine valves explanted for SVD underwent pathological study.
Results:
Nineteen patients (54%) were operated on urgently for prosthetic valve replacement. No intraoperative technical complications occurred, and only one patient underwent aortic root replacement. One patient (3%) died in-hospital. Prosthesis dysfunction was due to SVD in 27 patients, caused by cusp commissural tearing in 22. All the nine explanted valves submitted to pathological examination showed calcifications and lipid insudation. At histology, eight prostheses disclosed cholesterol clefts and all showed a chronic inflammatory infiltrate. Transmission electron microscopy disclosed the presence of calcific deposits on cell debris and collagen fibres and confirmed the presence of cholesterol clefts. After a mean follow-up of 50 ± 33 months, survivals at 1, 5 and 7 years were 91 ± 5, 56 ± 9 and 38 ± 13%, respectively.
Conclusions:
The CLOB reoperation is a feasible procedure, with satisfactory postoperative and mid-term survival results. Cusp tears, due to lipid and calcium deposits mostly targeting the commissures, seem to be the most important mechanism of SVD, resulting even in acute prosthetic incompetence and urgent reoperation.